RxSwift:Single实例：读取文件

1.swift

func loadText(from name: String) -> Single<String> {
    enum FileReadError: Error {
        case fileNotFount
        case unreadable
        case encodingFailed
    }

    return Single.create {
        single in
        let disposable = Disposables.create()
        guard let path = Bundle.main.path(forResource: name, ofType: "txt") else {
            single(.failure(FileReadError.fileNotFount))
            return disposable
        }
        guard let data = FileManager.default.contents(atPath: path) else {
            single(.failure(FileReadError.unreadable))
            return disposable
        }
        guard let contents = String(data: data, encoding: .utf8) else {
            single(.failure(FileReadError.encodingFailed))
            return disposable
        }
        single(.success(contents))
        return disposable
    }

}